Graviatational force field

By considering the centripetal force acting on a man, calculate the minimum period of rotation that the Earth would need to have about its axis if a man at the equator were to experience zero normal contact force.
Take radius of Earth=6400km

2. The attempt at a solution
this means the g=Fc(centripetral force)
to find v= square root of ( radius of the Earth and g)
g=9.81 N/kg and then sub it to T= (2pie x radius of Earth )/v
Where is the error? Does a zero normal force means the person is experiencing weightlessness due to a=g?

. where radius of the Earth is 6400km
But I can't get the ans=1.41hrs
I can only get 84.3hrs
square root of{Rg}=square root of (6400km X 35.3km/h)= 475
(R multiply by 2pie)divide by T= 40212/T
cross multiply them and I get 84.3hrs. Do u know where is the error?